Characterization of Complement C3 as a Glycyrrhizin (GL)-Binding Protein and the Phosphorylation of C3alpha by CK-2, Which Is Potently Inhibited by GL and Glycyrrhetinic Acid In Vitro
Autor: | Kenzo Ohtsuki, Yoshihito Shimoyama, Fumitaka Kawakami |
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Rok vydání: | 2003 |
Předmět: |
Protein Conformation
Protein Serine-Threonine Kinases Biochemistry chemistry.chemical_compound In vivo Synovial Fluid Glycyrrhiza medicine Humans Anaphylatoxin Phosphorylation Casein Kinase II Glycyrrhizin Molecular Biology Binding Sites Activator (genetics) Chemistry Arthritis Binding protein Complement C3 General Medicine Glycyrrhizic Acid Trypsin Molecular biology Complement C3a Glycyrrhetinic Acid Casein kinase 2 Protein Binding medicine.drug |
Zdroj: | Journal of Biochemistry. 133:231-237 |
ISSN: | 0021-924X |
Popis: | The physiological interaction between glycyrrhizin (GL) and serum complement C3, and the inhibitory effects of GL, glycyrrhetinic acid (GA), and a GA derivative (oGA) on the phosphorylation of C3 by casein kinase 2 (CK-2), were investigated in vitro. C3 was found to be a GL-binding protein (gbP), because (i) of its high affinity for a GL-affinity HPLC column; and (ii) both GL and GA induce conformational changes in C3. At least four trypsin-resistant fragments (p30, p25, p18, and p15) were detected when the (32)P-labeled C3alpha was digested with trypsin in the presence of 100 micro M GA. Two of these (p25 and p15) were immuno-precipitated with anti-C3a serum. Furthermore, it was found that C3a contains GL-binding domains, because (i) C3a (anaphylatoxin) could be selectively purified from the synovial fluids of patients with rheumatoid arthritis by GL-affinity column chromatography (HPLC); and (ii) purified human C3a has a high affinity for a GL-affinity column. In addition, C3alpha (p115) of C3 was effectively phosphorylated by CK-2 in the presence of poly-Arg (a CK-2 activator) in vitro. This phosphorylation was completely inhibited by 10 micro M oGA, 30 micro M GA, or 100 micro M GL. Taken together, these results suggest that the GL-induced inhibition of the physiological activities of C3a and C3alpha may be involved in the anti-inflammatory effect of GL in vivo. |
Databáze: | OpenAIRE |
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